1. Field of the Invention
This invention generally relates to automatic fluid shutoff devices. Such devices find use in applications where it is desired to provide for the automatic shut-off of a pressurized water line that has a leak to prevent damage to structures or to prevent waste of water. In particular, automatic fluid shutoff valves that shut-off with slow constant flow through the pipe and do not require electricity are desired in applications such as homes where the occupants may be absent or otherwise unaware of a slow leak in the water supply line.
2. Description of Related Art
Various types of automatic shutoff devices and valves are available to detect leaks and shut off water supply lines before serious damage occurs. Current automatic shutoff devices and valves that shut off during periods of slow, constant flow require a separate electrical power source. Alternatively they have features that are not compatible with shutting off home water supplies after long periods of slow, steady flow.
U.S. Pat. No. 4,589,435 of Aldrich et al. describes a water shutoff valve comprising a cylindrical body having a valve disk and water flow sensor. The sensor is connected to an electronic timer that resets to zero when water flow is interrupted. The valve automatically closes when there is a continuous flow of water for a predetermined amount of time. The timer may be set for selected time periods allowing the valve to stay open for short of long periods of time as required.
U.S. Patent Publication No. 2010/0193048 of Chang describes an overflow shutoff valve that is designed to automatically cut off water flow when water flows exceeds a certain amount. Its design allows for self-cleaning and it has an automatic resetting function. The valve consists of an outer body that has an inlet and outlet port with an internally installed rubber Venturi tube assembly, fixed flange, moving flange, coil spring and surge flow suppressing orifice. The valve automatically shuts off when lower pressure causes a rubber tube to be compressed by the water pressure. The overflow shutoff valve turns off when the supply water pressure drops below 5 psi.
U.S. Pat. No. 7,111,638 of Johnson describes a flexible connector that prevents excess flow of fluid when there is a rupture or separation of the connector. A spring biases the valve in an open position. The valve closes when the pressure exceeds a pre-determined amount after a time delay effected by a damping system that uses a variable volume damper chamber that includes a flexible bladder.
U.S. Pat. No. 7,503,341 of Achterman describes a flow shutoff valve that has a flow metering sleeve within a flow passage. The sleeve and passage form an annular space. The sleeve includes a flow metering aperture that is downstream from the annular space. A valve member is mounted within the sleeve. The valve may move between no flow, normal flow, and a shutoff position.
U.S. Pat. No. 8,485,220 of Gutierrez describes an automatic flow regulator valve designed to regulate water pressure from a liquid source outlet in the event of pressure surges or fluctuations. The regulator has a spring and sealing plate. The sealing plate moves based upon water pressure, moving the valve from an open state to a closed state.
Applicant(s) believe(s) that the material incorporated above is “non-essential” in accordance with 37 CFR 1.57, because it is referred to for purposes of indicating the background of the invention or illustrating the state of the art. However, if the Examiner believes that any of the above-incorporated material constitutes “essential material” within the meaning of 37 CFR 1.57(c)(1)-(3), applicant(s) will amend the specification to expressly recite the essential material that is incorporated by reference as allowed by the applicable rules.